Mutating Table Problem

If you need to update a mutating or constraining table, you could use a temporary table, a PL/SQL table, or a package variable to bypass these restrictions. For example, in place of a single AFTER row trigger that updates the original table, resulting in a mutating table error, you may be able to use two triggers-an AFTER row trigger that updates a temporary table, and an AFTER statement trigger that updates the original table with the values from the temporary table. (Entnommen von http://otn.oracle.com).